合成甲基叔丁基醚的沸石分子筛催化剂的研究

对合成甲基叔丁基醚 (MTBE)反应的几种沸石分子筛进行研究 ,认为催化剂的活性主要受催化剂的酸强度及酸中心数影响。催化剂酸性强 ,催化活性虽高 ,但MTBE选择性差 ;而中强酸中心是醚化反应的最佳酸中心。选择性与催化剂的结构和酸强度有关 ;对选择性较好的催化剂改性 ,增加中强酸的酸中心数 ,可以提高其活性。催化剂的使用寿命与催化剂酸性及结构有关。HY型和HUSY型分子筛的活性最高 ,但选择性差 ,寿命最短。而Hβ和HZSM -5分子筛活性较低 ,但选择性好 ,寿命较长。改性后的 β分子筛性能最佳。     

Laboratory column study for remediation of MTBE-contaminated groundwater using a biological two-layer permeable barrier

In this study, an in situ biological two-layer permeable reactive barrier system consisting of an oxygen-releasing material layer followed by a biodegradation layer was designed to evaluate the remediation effectiveness of MTBE-contaminated groundwater. The first layer containing calcium peroxide (CaO(2)) and other inorganic salts is to provide oxygen and nutrients for the immobilized microbes in the second layer in order to keep them in aerobic condition and maintain their normal metabolism. Furthermore, inorganic salts such as potassium dihydrogen phosphate (KH(2)PO(4)) and ammonium sulphate ((NH(4))(2)SO(4)) can also decrease the high pH caused by the alkali salt degraded from CaO(2). The second layer using granular expanded perlite as microbial carrier is able to biodegrade MTBE entering the barrier system. Batch experiments were conducted to identify the appropriate components of oxygen-releasing materials and the optimum pH value for the biodegradation of MTBE. At pH=8.0, the biodegradation efficiency of MTBE is the maximum and approximately 48.9%. A laboratory-scale experiment using two continuous upflow stainless-steel columns was then performed to evaluate the feasibility of this designed system. The fist column was filled with oxygen-releasing materials at certain ratio by weight. The second column was filled with expanded perlite granules immobilizing MTBE-degrading microbial consortium. Simulated MTBE-contaminated groundwater, in which dissolved oxygen (DO) content was 0mg/L, was pumped into this system at a flow rate of 500mL/d. Samples from the second column were analyzed for MTBE and its major degradation byproduct. Results showed that MTBE could be removed, and its metabolic intermediate, tert-butyl alcohol (TBA), could also be further degraded in this passive system.     

石油二厂MTBE装置工艺技术改造

抚顺石化分公司石油二厂原有的MTBE装置采用混相反应技术和绝热外循环反应技术 ,其生产能力为 2 .0× 1 0 4 t/a ,已不能满足新配方汽油发展的要求。装置能耗高 ,异丁烯转化率较国际先进水平低 ,为此 ,石油二厂将MTBE装置进行改造 ,采用北京设计院与齐鲁石化公司研究院及哈尔滨炼油厂经多年研究和工程开发形成的专有技术———混相床催化蒸馏深度转化组合工艺 ,与常规的二反四塔流程相比 ,深度转化组合工艺具有流程短、转化率高、易于操作、催化剂用量小和节省公用工程等优点。装置改造采用新技术 ,但尽量利用原有的设备 ,包括反应器、塔器、冷换设备、机泵、仪表和配电设施 ,确属工艺需要则予更换 ,以节约投资。     

分子筛催化合成甲基叔丁基醚反应宏观动力学

在改性β分子筛液相催化异丁烯与甲醇合成甲基叔丁基醚反应本征动力学的基础上 ,考察了催化剂粒度变化对反应的影响 ,建立了宏观动力学方程。用最小二乘法和数值积分法对动力学试验数据进行拟合 ,得到有效扩散系数Def=1 8× 10 - 8exp[-1914 1/(RT) ] ,并将异丁烯转化率实验值与由宏观动力学方程的计算值相比较。结果表明 ,所建立的宏观动力学方程能很好地描述存在内扩散影响的分子筛液相催化醚化反应过程。并采用模型方程预测了反应条件和催化剂粒度对醚化反应结果的影响     

MTBE装置反应精馏塔工艺操作条件的探讨及优化

从反应精馏的工艺操作入手 ,针对操作过程中出现的反应精馏塔内二聚反应的发生及控制、反应精馏塔进料中甲醇含量的探讨及优化、反应精馏塔进料温度的调节及优化、反应精馏塔釜所带碳四及控制、反应精馏塔内二甲醚副反应的发生及控制等问题 ,进行探讨、分析并进行优化     

Effects of polymer solvents on the performance of cellulose acetate membranes in methanol/methyl tertiary butyl ether separation

The performances of cellulose acetate membranes prepared with casting solutions, with acetone, dimethylformamide (DMF), and N‐methylpyrrolidone (NMP) as solvents, were studied in a series of methanol/methyl tertiary butyl ether separation experiments. The flux and selectivity of the membrane samples were affected by the type of solvent used to prepare the casting solution. The sample with DMF consistently gave the highest selectivity and lowest flux, followed by the samples with NMP and acetone. The differences in the performances were attributed to the effects of the volatility and evaporation rates of the solvents. Scanning electron microscopy and atomic force microscopy techniques were used for comparing the morphologies of the membranes. In addition, we used Raman spectroscopy as a novel technique to study the sorption selectivities of the membrane samples prepared with the three different solvents. In a parallel study, the relation between the polymer concentration in the casting solution and the morphology and performance of the membrane samples was studied. Under similar preparation conditions, the morphology of the membrane changed from being porous to being dense when the membrane was prepared with casting solutions with increasing polymer concentration. Also, the selectivity increased and the permeability decreased with increasing polymer concentration in the casting solution. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2882–2895, 2001     

甲基叔丁基醚反应精馏过程联合控制方案设计

基于非平衡级假设建立了甲基叔丁基醚反应精馏过程的动态严格机理模型。在过程模型基础上进行了过程控制方案的设计,提出了一种基于醇烯比软测量模型的产品质量／转化率联合控制方案,并通过仿真计算和其它常规控制方案进行了对比。结果表明,该联合控制方案优于单端质量控制方案,能够有效满足MTBE反应精馏过程的多指标控制要求。     

化工型MTBE的工业生产技术

介绍了化工型ＭＴＢＥ的工艺过程，工艺特点及Ｃ４醚化过程中ＭＳＢＥ副反应的控制方法。并以实例说明采用该工艺生产的ＭＴＢＥ完全可满足裂解制备高纯度异丁烯的需要。     

MTBE装置的流程模拟

介绍在MTBE混相床-催化蒸馏装置工艺设计过程中使用ASPENPLUS模拟软件开发包括化学动力学反应在内的全流程模拟的模型。实践证明，模拟结果与装置标定数据基本吻合。为工艺设计人员提供了参考，并大大提高了设计速度和质量。     

化工型膨胀床合成MTBE的技术

抚顺石化公司石油二厂２０ｋｔ／ａ化工型膨胀床合成ＭＴＢＥ工业装置，采用了抚顺石化公司石油二厂、洛阳石化工程公司和抚顺石油学院联合开发的技术，所用原料是该炼油厂混合Ｃ４中的异丁烯和甲醇在树脂催化剂作用下醚化，过程中除生成纯度高的ＭＴＢＥ外，抽余Ｃ４中异丁烯、ＤＭＥ、ＭＴＢＥ、甲醇均达到精细化工原料的要求。装置经过几年运转和完善，各项指标均达到或超过设计指标。